The present invention is directed towards registering a document to be copied on the glass platen of a copier, and more particularly, to present a set of visible document outlines as an aid to precise document registration.
An original document to be copied in an electrophotographic copying machine is typically placed on the glass platen of the machine in a position which registers the document at the proper location to effect the required imaging at the photoreceptor followed by subsequent transfer to the output copy medium. Registration systems are referred to as edge registered (document is registered along the left or right edge registration guide) or corner edge registered (document is registered along the edge and along a top or bottom corner of the registration guide). The edge and corner registration guides typical of the prior art are located adjacent to the glass platen and have a slightly raised surface so that the document can be aligned against the edge. There is a presistent problem present with casual operation of the machine in quickly determining the exact registration position for a document with differing size or differing orientation (long-edge or short-edge feed). While indicia may be present along the registration edge to assist in proper location selection, yet it may be confusing to the casual operator and produce operation and subsequent unwanted copies until the proper location is finally found. From a human factor point of view it would be desirable to have outlines of documents of various sizes visible to an operator at the platen surface and prior to operation so that the operator could simply match the document to be copied with an outline position and place the document within the identified outline borders. In order to provide this type of feature, however, a fundamental technical requirement must be met; that is, the set of patterns seen by the operator must be invisible during the subsequent imaging or copy operation, else the outline would effect the output copy adversely. This requirement rules out proposed solutions such as etching the patterns into the glass of the platen, since the etched portions would be in the optical path of the document image and would create unwanted diffusion and reflection of light.
According to a first aspect of the present invention, a set of patterns are visible to an operator prior to start of the copy operation and are then moved out of the exposure path upon initiation of a copying cycle. This is accomplished in a first embodiment by locating a retractable "window shade" film substrate beneath the platen, the substrate having the document sizes formed, in outline, within the substrate. The operator can easily find the outline pattern to match the document to be copied and place the document thereon. Upon initiation of the copying mode, the substrate is retracted and is no longer visible to the operator, nor to the optical system. According to a second aspect of the invention, a platen cleaning member is attached to the substrate to provide an additional function as the substrate moves to the retracted position.
More particularly, the present invention relates to an electrophotographic copying machine provided with a glass platen for placing documents to be copied thereon and includes a document registration guide assembly comprising,
a flexible substrate positioned beneath said platen, underlying the document exposure area, said substrate having formed therein visible outlines of a plurality of document sizes, each document size pattern corresponding to a correctly registered document position on the overlying platen surface, and means for positioning said substrate beneath said platen so that said outlines are visible during a non-copying mode, and means adapted to move the substrate out of the exposure area when a copy mode cycle is initiated.
A search of the prior art has identified a number of patents disclosing various document positioning mechanisms, none of which discloses the above-described concept of the present invention. Representative of the prior art are the following patents:
U.S. Pat. No. 4,595,285 to Miwa et al. discloses an electrophotographic copying machine comprising a translucent document cover with paper size index lines for providing accurate document positioning on a document table during a manual copying process. The translucent cover 3 pivotally rotates in and out of position over a glass plate. The cover includes paper size index lines 7 for indicating a copy size outline for various size papers to provide accurate document positioning on a glass plate 2. (See col. 2, lines 29-37 and FIG. 1.) Cover 3 also includes marks 70-79 for indicating various image size ratios for magnifying or reducing the copy document. (See col. 3, lines 28-50 and FIG. 5.)
U.S. Pat. No. 4,436,402 to Seimiya et al. discloses a copy board comprising index plate position indexes 3a, 4a, 4b, 5b of various sizes which are used to correlate document positioning with the optics of a copying machine. (See col. 3, lines 48-54 and FIG. 2.)
U.S. Pat. No. 4,415,261 to Yukawa et al. discloses a copying machine comprising a platen cover which includes color marks or patterns for properly positioning an original on a transparent plate. (See col. 4, lines 1-9).
U.S. Pat. No. 4,783,679 to Anzai discloses an original-setting table 2 for properly aligning document of different sizes with the optics of a copying machine.
U.S. Pat. No. 4,721,981 to Rauen et al. discloses a copying machine comprising a retractable "curtain shade" platen cover 24, i.e., a thin flexible film, that reels out from a scroll 26 into position over and above a document platen 14 during a copying process. See col. 9, lines 5-16 and 44-56 and FIG. 1.